Merge Two Sorted Lists 分类： Leetcode（排序） 2015-04-08 21:59 24人阅读 评论(0) 收藏

Merge Two Sorted Lists

/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     ListNode *next;
*     ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *mergeTwoLists(ListNode *l1, ListNode *l2) {
if(!l1) return l2;
if(!l2) return l1;
ListNode dummy(-1);
ListNode *p = &dummy;
while(l1 &&l2) {
if(l1->val >= l2->val) {
p->next = l2;
p = l2;
l2 = l2->next;
}
else {
p->next = l1;
p = l1;
l1 = l1->next;
}
}
if(l1) p->next = l1;
else p->next = l2;
return dummy.next;

}
};